Viscoelastic properties of dilute macromolecular solutions can provide information about molecular size, shape, and flexibility, and the polymerization of subunits. The Birnboim-Schrag multiple-lumped resonator will be used to study, at very low concentrations, biomacromolecules such as fibrinogen dimer, paramyosin, tropomyosin, soluble collagen, soluble elastin, F-actin, shear-degraded and fractionated DNA, DNA intercalated with small molecules, and helical polyamino acids, in the frequency range from 100 to 8000 Hz. The frequency dependence of the storage and loss shear moduli will be related to features such as partial flexibility of long helical structures, deformability of corpuscular proteins, and aspects of helix-coil transitions. Studies of the first stages of polymerization of fibrin, and of the elastic and viscoelastic properties of fibrin clots, will be related to the secondary forces holding the fibrin units together in the absence of ligation and the primary bonds introduced when ligation is effected. Measurements of creep and stress relaxation will be made on clots with and without ligation, with varying coarseness of structure, formed by thrombin and other enzymes capable of activating polymerization. Measurements of viscoelastic properties, including stress relaxation and elastic recovery, will be made on fibrin films and collagen films to elucidate the molecular processes associated with deformation and relaxation, supplemented by observations of X-ray patterns and electron micrographs.